U.S. patent application number 12/692321 was filed with the patent office on 2011-07-28 for moving large dynamic datasets via incremental change synchronization.
This patent application is currently assigned to MICROSOFT CORPORATION. Invention is credited to BRADFORD R. CLARK, DMITRI GAVRILOV, JAMES C. KLEEWEIN, AYLA KOL, BRIAN T. KRESS, NARESH SUNDARAM.
Application Number | 20110185136 12/692321 |
Document ID | / |
Family ID | 44309847 |
Filed Date | 2011-07-28 |
United States Patent
Application |
20110185136 |
Kind Code |
A1 |
GAVRILOV; DMITRI ; et
al. |
July 28, 2011 |
MOVING LARGE DYNAMIC DATASETS VIA INCREMENTAL CHANGE
SYNCHRONIZATION
Abstract
Incremental change synchronization for moving large data sets
may be provided. Source data to be moved may be identified and a
snapshot of the data may be created. The data may be moved to a new
datastore and a second snapshot may be created. The snapshots may
be compared to identify any data elements that have been modified
and the modified elements may be copied to the new datastore.
Inventors: |
GAVRILOV; DMITRI; (REDMOND,
WA) ; CLARK; BRADFORD R.; (DUVALL, WA) ;
KLEEWEIN; JAMES C.; (KIRKLAND, WA) ; KOL; AYLA;
(SAMMAMISH, WA) ; KRESS; BRIAN T.; (WOODINVILLE,
WA) ; SUNDARAM; NARESH; (REDMOND, WA) |
Assignee: |
MICROSOFT CORPORATION
REDMOND
WA
|
Family ID: |
44309847 |
Appl. No.: |
12/692321 |
Filed: |
January 22, 2010 |
Current U.S.
Class: |
711/162 ;
711/E12.001; 711/E12.103 |
Current CPC
Class: |
G06F 16/273 20190101;
G06F 16/214 20190101 |
Class at
Publication: |
711/162 ;
711/E12.001; 711/E12.103 |
International
Class: |
G06F 12/16 20060101
G06F012/16; G06F 12/00 20060101 G06F012/00 |
Claims
1. A method for moving data, the method comprising: identifying a
plurality of source data; creating a first state snapshot of the
source data; copying each of the plurality of source data to a
destination datastore; creating a second state snapshot of the
source data; determining whether the second state snapshot
comprises at least one element of source data not present in the
first state snapshot; and in response to determining that the
second state snapshot comprises the at least one element of source
data not present in the first state snapshot, copying the at least
one element of source data not present in the first state snapshot
to the destination datastore.
2. The method of claim 1, further comprising modifying an element
of the source data while copying each of the plurality of source
data to the destination datastore.
3. The method of claim 2, wherein the modification to the element
of the source data comprises at least one of the following:
receiving the element of the source data, deleting the element of
the source data, and moving the element of the source data.
4. The method of claim 2, further comprising assigning an
incremental change number to the modified element of the source
data.
5. The method of claim 4, wherein the first state snapshot
comprises at least one incremental change number associated with
the source data prior to modifying the element of the source
data.
6. The method of claim 5, wherein the second state snapshot
comprises the assigned incremental change number of the modified
element of the source data.
7. The method of claim 6, wherein determining whether the second
state snapshot comprises at least one element of source data not
present in the first state snapshot comprises determining whether
the at least one incremental change number of the first state
snapshot differs from the assigned incremental change number of the
second state snapshot.
8. The method of claim 1, further comprising determining whether
the second state snapshot comprises a number of changes to the
source data greater than a threshold.
9. The method of claim 8, wherein the threshold comprises 100
changes.
10. The method of claim 8, further comprising: in response to
determining that the second state snapshot comprises the number of
changes to the source data greater than the threshold, copying each
of a plurality of data elements associated with the changes to the
destination datastore.
11. The method of claim 8, further comprising: in response to
determining that the second state snapshot comprises the number of
changes to the source data less than the threshold, locking the
source datastore from client access.
12. A system for copying a block of data, the system comprising: a
memory storage; and a processing unit coupled to the memory
storage, wherein the processing unit is operative to: provide
access from a client application to a plurality of data elements,
create a first state snapshot of the plurality of data elements on
a first data storage device, copy the plurality of data elements
from the first data storage device to a second data storage device
while continuing to provide access to the plurality of data
elements from the client application, create a second state
snapshot of the plurality of data elements on the first data
storage device, determine, according to a comparison of the first
state snapshot and the second state snapshot, whether more than a
threshold number of modifications to the plurality of data elements
occurred during the copy of the plurality of data elements from the
first data storage device to a second data storage device, and in
response to determining that more than a threshold number of
modifications to the plurality of data elements occurred during the
copy of the plurality of data elements, copy the modified data
elements from the first data storage device to the second data
storage device while continuing to provide access to the plurality
of data elements from the client application.
13. The system of claim 12, wherein the threshold number of
modifications comprises 100 modifications.
14. The system of claim 12, wherein the processing unit is further
operative to: in response to determining that more than the
threshold number of modifications to the plurality of data elements
did not occur during the copy of the plurality of data elements,
lock access to the plurality of data elements from the client
application.
15. The system of claim 14, wherein the processing unit is further
operative to: determine whether a number of modifications to the
plurality of elements less than the threshold number of
modifications occurred during the copy of the plurality of data
elements, copy the modified data elements from the first data
storage device to the second data storage device while denying
access to the plurality of data elements from the client
application.
16. The system of claim 15, wherein the processing unit is further
operative to provide access to the plurality of data elements on
the second data storage device from the client application.
17. The system of claim 14, wherein the processing unit is further
operative to: in response to determining that more than the
threshold number of modifications to the plurality of data elements
did not occur during the copy of the plurality of data elements,
determine whether a current time comprises a maintenance window
time; and in response to determining that the current time does not
comprise the maintenance window time, continue to provide access to
the plurality of data elements from the client application until
the current time comprises the maintenance window time.
18. The system of claim 12, wherein the first state snapshot
comprises at least one change number associated with at least one
most recently modified element of the plurality of data elements
prior to copying the plurality of data elements from the first data
storage device to the second data storage device.
19. The system of claim 12, wherein the second state snapshot
comprises at least one change number associated with at least one
most recently modified element of the plurality of data elements
after copying the plurality of data elements from the first data
storage device to the second data storage device.
20. A computer-readable medium which stores a set of instructions
which when executed performs a method for copying data with change
synchronization, the method executed by the set of instructions
comprising: identifying a plurality of source data on a source
datastore; creating a first state snapshot of the source data;
determining, for each element of the plurality of source data,
whether the element has been deleted since the creation of the
first state snapshot; in response to determining that the element
has not been deleted, determining whether the element has been
modified since the creation of the first state snapshot; in
response to determining that the element has been modified since
the creation of the first state snapshot, copying the modified
element to a destination datastore; in response to determining that
the element has not been modified since the creation of the first
snapshot, copying the element as it exists in the first state
snapshot to a destination datastore; creating a second state
snapshot of the source data; determining whether the second state
snapshot comprises a plurality of data elements greater than a
threshold amount not present in the first state snapshot, wherein
the threshold amount comprises at least one of the following: a
number of the data elements and an amount of storage used by the
data elements; in response to determining that the second state
snapshot comprises the plurality of data elements greater than a
threshold amount not present in the first state snapshot, copying
the plurality of data elements to the destination datastore; in
response to determining that the second state snapshot comprises
the plurality of data elements less than a threshold amount not
present in the first state snapshot: locking the source datastore
from further access by a client application associated with the
source data, copying the plurality of data elements to the
destination datastore, and directing the client application to
access the destination datastore for interaction with the source
data.
Description
RELATED APPLICATION
[0001] Related U.S. patent application Ser. No. ______ filed on
even date herewith entitled "Massive Structured Data Transfer
Optimizations for High-Latency, Low-Reliability Networks", and
assigned to the assignee of the present application, is hereby
incorporated by reference.
BACKGROUND
[0002] Incremental change synchronizations provide a process for
transferring large amounts of dynamic data. In some situations,
data sets may need to be moved from one datastore to another. For
example, a database for a mail server may need to be moved to new
hardware, due to data management policies or a hardware failure.
Such a database may be in a constant state of flux, such as where a
number of users are frequently accessing their mail data, receiving
new mail messages, and moving, responding to, and deleting
messages. In conventional systems, moving the data requires locking
the database and preventing user access to the data for the entire
duration of the move. This can cause problems because such a move
may take an unacceptably long downtime during which users are
unable to access their data.
SUMMARY
[0003] Incremental change synchronization may be provided. This
Summary is provided to introduce a selection of concepts in a
simplified form that are further described below in the Detailed
Description. This Summary is not intended to identify key features
or essential features of the claimed subject matter. Nor is this
Summary intended to be used to limit the claimed subject matter's
scope.
[0004] Incremental change synchronization for moving large data
sets may be provided. Source data to be moved may be identified and
a snapshot of the data may be created. The data may be moved to a
new datastore and a second snapshot may be created. The snapshots
may be compared to identify any data elements that have been
modified and the modified elements may be copied to the new
datastore.
[0005] Both the foregoing general description and the following
detailed description provide examples and are explanatory only.
Accordingly, the foregoing general description and the following
detailed description should not be considered to be restrictive.
Further, features or variations may be provided in addition to
those set forth herein. For example, embodiments may be directed to
various feature combinations and sub-combinations described in the
detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The accompanying drawings, which are incorporated in and
constitute a part of this disclosure, illustrate various
embodiments of the present invention. In the drawings:
[0007] FIG. 1 is a block diagram of an operating environment;
[0008] FIG. 2 is a flow chart of a method for providing optimized
data transfer; and
[0009] FIG. 3 is a block diagram of a system including a computing
device.
DETAILED DESCRIPTION
[0010] The following detailed description refers to the
accompanying drawings. Wherever possible, the same reference
numbers are used in the drawings and the following description to
refer to the same or similar elements. While embodiments of the
invention may be described, modifications, adaptations, and other
implementations are possible. For example, substitutions,
additions, or modifications may be made to the elements illustrated
in the drawings, and the methods described herein may be modified
by substituting, reordering, or adding stages to the disclosed
methods. Accordingly, the following detailed description does not
limit the invention. Instead, the proper scope of the invention is
defined by the appended claims.
[0011] Incremental change synchronization (ICS) for moving large
datasets may be provided. Consistent with embodiments of the
present invention, the transfer of a large block of data, such as a
large (e.g., 10 GB) mailbox comprising potentially hundreds and/or
thousands of messages, may be accomplished with reduced downtime.
Before the data move begins, a state snapshot of the source mailbox
may be made. Then, the mailbox data may be enumerated and copied
item by item and/or in batches. Any changes that occur while the
data is being copied may be enumerated using ICS at the end of the
move, and the changes may be applied to the destination database.
The final round of incremental synchronization may be performed
while the source mailbox is locked (i.e., protected from
modifications).
[0012] FIG. 1 is a block diagram of an operating environment 100
for providing incremental change synchronization. Operating
environment 100 may comprise a first server 110 comprising a source
datastore 115 and a second server 120 comprising a target datastore
125. Operating environment 100 may further comprise a client
application 130. First server 110, second server 120, and/or client
application 130 may communicate over a network 140. Consistent with
embodiments of the invention, source datastore 115 and target
datastore 125 may be associated with the same server, such as two
hard drives on first server 110.
[0013] Client application 130 may comprise, for example, a mail
application such as Outlook.RTM., as provided by Microsoft.RTM.
Corporation of Redmond, Wash. The mail application may store a
local copy of a mailbox file associated with source datastore 115.
First server 110 may be operative as a mail server for receiving
and storing messages associated with the server's copy of the
mailbox file. Client application 130 may periodically connect to
first server 110 to determine whether any changes have occurred to
the mailbox file and update the local copy accordingly.
[0014] Consistent with embodiments of the invention, ICS may be
used to update a local copy of the data associated with source
datastore 115 as well as moving the data from one datastore or
server to another. In ICS, each element of data may be assigned a
sequential change number. For example, when each mail message is
received, it may be assigned a change number that is incremented
for each message and/or other change made to a data element. A
first received message may have a change number, for example, of
4001. A second received message may be assigned a change number of
4002. If a user then modifies the first message, such as by moving
it to a different folder within the mailbox file structure, the
first message may be assigned a new change number of 4003. The next
received message may then be assigned a change number of 4004.
[0015] The change numbers may be used to create a snapshot of the
state of the data. For example, when a user instantiates client
application 130, it may connect to source datastore 115 to create a
local copy of the user's associated data. A snapshot of this local
copy may comprise a latest change number of any element of the
associated data, such as 4004. Client application 130 may then
periodically connect to source datastore 115 to determine whether
any associated data elements have a later change number than 4004,
and retrieve those new or modified elements to update the local
copy and create a new snapshot. Consistent with embodiments of the
invention, change numbers may be associated with data groupings,
such as folders, rather than and/or in addition to individual data
elements. For example, each time a message in a folder is added,
deleted, moved, or otherwise modified, the change number of the
folder may be incremented. In such a case, the snapshot of the data
may comprise an array, a hash, a string, and/or a similar structure
enumerating the change numbers for all of the folders associated
with the data.
[0016] FIG. 2 is a flow chart setting forth the general stages
involved in a method 200 consistent with an embodiment of the
invention for providing data transfer optimizations. Method 200 may
be implemented using a computing device 300 as described in more
detail below with respect to FIG. 3. Ways to implement the stages
of method 200 will be described in greater detail below. Method 200
may begin at starting block 205 and proceed to stage 210 where
computing device 300 may identify source data to be moved. For
example, first server 110 may identify a mailbox file comprising a
plurality of data elements stored in source datastore 115 to be
moved to target datastore 125 on second server 120.
[0017] From stage 210, method 200 may advance to stage 215 where
computing device 300 may create a state snapshot of the identified
source data. For example, first server 110 may determine and store
a change number associated with a most recently received, modified,
moved, and/or deleted data element of the source data.
[0018] After creating the initial snapshot at stage 215, method 200
may advance to stage 220 where computing device 300 may iterate
through each element of the data in the initial snapshot. At stage
225, computing device 300 may determine whether the data element
has been deleted since the snapshot was taken. If so, method 200
may return to stage 220 and iterate to the next element. That is,
if an element has been deleted, it may not be copied.
[0019] Otherwise, method 200 may advance to stage 230 where
computing device 300 may determine whether the data element has
been modified since the initial snapshot was taken. For example, a
message associated with data comprising a user's mailbox may be
moved to another folder. If the element has been modified, method
200 may advance to stage 235 where computing device 300 may copy
the element as modified to target datastore 125. Otherwise, method
200 may advance to stage 240 where computing device 300 may copy
the original element to target datastore 125.
[0020] From stage 235 or stage 240, method 200 may advance to stage
245 where computing device 300 may determine whether any more
elements remain to be copied. If so, method 200 may return to stage
220 and iterate to the next data element. Consistent with
embodiments of the invention, client access to source datastore 115
may remain active during the copying stages.
[0021] Otherwise, method 200 may advance to stage 250 where
computing device 300 may create a second snapshot of the source
data. For example, the second snapshot may comprise a change number
associated with a most recently modified element of the source
data, such as an element that was modified during the copy stages
235 and 240.
[0022] From stage 250, method 200 may advance to stage 255 where
computing device 300 may determine how many data elements changed
during the copy stage 235 and 240 and whether the number of changes
exceeds a threshold amount. For example, the threshold may comprise
100 changes to elements. If so, method 200 may return to stage 215
and create a new base snapshot. Any changes identified between the
new base snapshot and the initial snapshot may then be copied
according to the stages described above. Consistent with
embodiments of the invention, the second snapshot created at stage
250 may be used as the new base snapshot and method 200 may return
to stage 220 to iterate through the changed elements.
[0023] Method 200 may then advance to stage 260 where computing
device 300 may lock the identified data in source datastore 115.
For example, client application 130 may be denied access to source
datastore 115 during a periodic update performed by client
application 130. Such a denial may comprise an error operative to
inform client application 130 that its master data has moved and
may comprise data identifying the new location, such as target
datastore 125. Consistent with embodiments of the invention, client
application 130 may be unable to access data in either source
datastore 115 or target datastore 125 while data access is locked.
Client application 130 may be operative to periodically retry
either and/or both datastores until the lock is removed.
[0024] Computing device 300 may also be operative to limit the
number of repeating loops from stage 255 to stage 215 or stage 220.
That is, if the number of changes exceeds the threshold level on
more than some second threshold number of occasions, such as ten,
method 200 may proceed onwards to stage 260 rather than repeating
indefinitely.
[0025] Further consistent with embodiments of the invention,
computing device 300 may be operative to determine whether a
current time is during a maintenance window before locking access
to the data. For example, computing device 300 may only be
permitted to lock access between 2:00 AM and 5:00 AM. If the
current time is not within such a window, computing device 300 may
continue to periodically copy data from source datastore 115 to
target datastore 125 according to the stages of method 200
described above until the maintenance window arrives and then lock
the data.
[0026] From stage 260, method 200 may advance to stage 265 where
computing device 300 may copy the remaining modified data elements.
For example, in some cases, each iteration of the stages from 215
through 255 may result in less time needed and fewer modified
elements to copy until the number of modified elements is below the
threshold number. The threshold number may be set so as to minimize
the amount of time needed to copy the remaining modified elements
and so minimize the amount of time the data is locked from client
access.
[0027] Once the remaining modified elements are copied in stage
265, method 200 may advance to stage 270 where computing device 300
may direct the client application to the new data location. For
example, computing device 300 may send a message to client
application 130 directing it to target datastore 125. Consistent
with embodiments of the invention, client application 130 may
periodically query servers on network 140, such as first server 110
and second server 120, for location information associated with its
needed data. In response to such a query, first server 110 and/or
second server 120 may reply with the location information needed
for client application 130 to access target datastore 125. Method
200 may then end at stage 275.
[0028] An embodiment consistent with the invention may comprise a
system for moving data. The system may comprise a memory storage
and a processing unit coupled to the memory storage. The processing
unit may be operative to identify source data, create a first state
snapshot of the source data, copy each of the plurality of source
data to a destination datastore, create a second state snapshot of
the source data, determine whether the second state snapshot
comprises at least one element of source data not present in the
first state snapshot, and, if so, copy the at least one element of
source data not present in the first state snapshot to the
destination datastore.
[0029] Another embodiment consistent with the invention may
comprise a system for copying a block of data. The system may
comprise a memory storage and a processing unit coupled to the
memory storage. The processing unit may be operative to provide
access from a client application to a plurality of data elements,
create a first state snapshot of the plurality of data elements on
a first data storage device, copy the plurality of data elements
from the first data storage device to a second data storage device
while continuing to provide access to the plurality of data
elements from the client application, create a second state
snapshot of the plurality of data elements on the first data
storage device, determine, according to a comparison of the first
state snapshot and the second state snapshot, whether more than a
threshold number of modifications to the plurality of data elements
occurred during the copy of the plurality of data elements from the
first data storage device to a second data storage device, and, if
so, copy the modified data elements from the first data storage
device to the second data storage device while continuing to
provide access to the plurality of data elements from the client
application.
[0030] Yet another embodiment consistent with the invention may
comprise a system for copying data with change synchronization. The
system may comprise a memory storage and a processing unit coupled
to the memory storage. The processing unit may be operative to
identify source data on a source datastore, create a first state
snapshot of the source data, and determine, for each element of the
plurality of source data, whether the element has been deleted
and/or modified since the creation of the first state snapshot. If
the element has been deleted, the processing unit may be operative
to skip the element and iterate to the next one. If the element has
been modified, the processing unit may be operative to copy the
most up to date version of the data element. An unmodified element
may be copied in its original state from when the first state
snapshot was taken. The processing unit may then be operative to
create a second state snapshot of the source data and determine
whether the second state snapshot comprises a plurality of data
elements greater than a threshold amount not present in the first
state snapshot. If so, the processing unit may copy the plurality
of modified data elements to the destination datastore. Otherwise,
the processing unit may be operative to lock the source datastore
from further access by a client application associated with the
source data, copy the plurality of data elements to the destination
datastore, and direct the client application to access the
destination datastore for interaction with the source data.
[0031] FIG. 3 is a block diagram of a system including computing
device 300. Consistent with an embodiment of the invention, the
aforementioned memory storage and processing unit may be
implemented in a computing device, such as computing device 300 of
FIG. 3. Any suitable combination of hardware, software, or firmware
may be used to implement the memory storage and processing unit.
For example, the memory storage and processing unit may be
implemented with computing device 300 or any of other computing
devices 318, in combination with computing device 300. The
aforementioned system, device, and processors are examples and
other systems, devices, and processors may comprise the
aforementioned memory storage and processing unit, consistent with
embodiments of the invention. Furthermore, computing device 300 may
comprise an operating environment for system 100 as described
above. System 100 may operate in other environments and is not
limited to computing device 300.
[0032] With reference to FIG. 3, a system consistent with an
embodiment of the invention may include a computing device, such as
computing device 300. In a basic configuration, computing device
300 may include at least one processing unit 302 and a system
memory 304. Depending on the configuration and type of computing
device, system memory 304 may comprise, but is not limited to,
volatile (e.g. random access memory (RAM)), non-volatile (e.g.
read-only memory (ROM)), flash memory, or any combination. System
memory 304 may include operating system 305, one or more
programming modules 306, such as a change synchronizer 320.
Operating system 305, for example, may be suitable for controlling
computing device 300's operation. Furthermore, embodiments of the
invention may be practiced in conjunction with a graphics library,
other operating systems, or any other application program and is
not limited to any particular application or system. This basic
configuration is illustrated in FIG. 3 by those components within a
dashed line 308.
[0033] Computing device 300 may have additional features or
functionality. For example, computing device 300 may also include
additional data storage devices (removable and/or non-removable)
such as, for example, magnetic disks, optical disks, or tape. Such
additional storage is illustrated in FIG. 3 by a removable storage
309 and a non-removable storage 310. Computer storage media may
include volatile and nonvolatile, removable and non-removable media
implemented in any method or technology for storage of information,
such as computer readable instructions, data structures, program
modules, or other data. System memory 304, removable storage 309,
and non-removable storage 310 are all computer storage media
examples (i.e memory storage.) Computer storage media may include,
but is not limited to, RAM, ROM, electrically erasable read-only
memory (EEPROM), flash memory or other memory technology, CD-ROM,
digital versatile disks (DVD) or other optical storage, magnetic
cassettes, magnetic tape, magnetic disk storage or other magnetic
storage devices, or any other medium which can be used to store
information and which can be accessed by computing device 300. Any
such computer storage media may be part of device 300. Computing
device 300 may also have input device(s) 312 such as a keyboard, a
mouse, a pen, a sound input device, a touch input device, etc.
Output device(s) 314 such as a display, speakers, a printer, etc.
may also be included. The aforementioned devices are examples and
others may be used.
[0034] Computing device 300 may also contain a communication
connection 316 that may allow device 300 to communicate with other
computing devices 318, such as over a network in a distributed
computing environment, for example, an intranet or the Internet.
Communication connection 316 is one example of communication media.
Communication media may typically be embodied by computer readable
instructions, data structures, program modules, or other data in a
modulated data signal, such as a carrier wave or other transport
mechanism, and includes any information delivery media. The term
"modulated data signal" may describe a signal that has one or more
characteristics set or changed in such a manner as to encode
information in the signal. By way of example, and not limitation,
communication media may include wired media such as a wired network
or direct-wired connection, and wireless media such as acoustic,
radio frequency (RF), infrared, and other wireless media. The term
computer readable media as used herein may include both storage
media and communication media.
[0035] As stated above, a number of program modules and data files
may be stored in system memory 304, including operating system 305.
While executing on processing unit 302, programming modules 306
(e.g. change synchronizer 320) may perform processes including, for
example, one or more of method 200's stages as described above. The
aforementioned process is an example, and processing unit 302 may
perform other processes. Other programming modules that may be used
in accordance with embodiments of the present invention may include
electronic mail and contacts applications, word processing
applications, spreadsheet applications, database applications,
slide presentation applications, drawing or computer-aided
application programs, etc.
[0036] Generally, consistent with embodiments of the invention,
program modules may include routines, programs, components, data
structures, and other types of structures that may perform
particular tasks or that may implement particular abstract data
types. Moreover, embodiments of the invention may be practiced with
other computer system configurations, including hand-held devices,
multiprocessor systems, microprocessor-based or programmable
consumer electronics, minicomputers, mainframe computers, and the
like. Embodiments of the invention may also be practiced in
distributed computing environments where tasks are performed by
remote processing devices that are linked through a communications
network. In a distributed computing environment, program modules
may be located in both local and remote memory storage devices.
[0037] Furthermore, embodiments of the invention may be practiced
in an electrical circuit comprising discrete electronic elements,
packaged or integrated electronic chips containing logic gates, a
circuit utilizing a microprocessor, or on a single chip containing
electronic elements or microprocessors. Embodiments of the
invention may also be practiced using other technologies capable of
performing logical operations such as, for example, AND, OR, and
NOT, including but not limited to mechanical, optical, fluidic, and
quantum technologies. In addition, embodiments of the invention may
be practiced within a general purpose computer or in any other
circuits or systems.
[0038] Embodiments of the invention, for example, may be
implemented as a computer process (method), a computing system, or
as an article of manufacture, such as a computer program product or
computer readable media. The computer program product may be a
computer storage media readable by a computer system and encoding a
computer program of instructions for executing a computer process.
The computer program product may also be a propagated signal on a
carrier readable by a computing system and encoding a computer
program of instructions for executing a computer process.
Accordingly, the present invention may be embodied in hardware
and/or in software (including firmware, resident software,
micro-code, etc.). In other words, embodiments of the present
invention may take the form of a computer program product on a
computer-usable or computer-readable storage medium having
computer-usable or computer-readable program code embodied in the
medium for use by or in connection with an instruction execution
system. A computer-usable or computer-readable medium may be any
medium that can contain, store, communicate, propagate, or
transport the program for use by or in connection with the
instruction execution system, apparatus, or device.
[0039] The computer-usable or computer-readable medium may be, for
example but not limited to, an electronic, magnetic, optical,
electromagnetic, infrared, or semiconductor system, apparatus,
device, or propagation medium. More specific computer-readable
medium examples (a non-exhaustive list), the computer-readable
medium may include the following: an electrical connection having
one or more wires, a portable computer diskette, a random access
memory (RAM), a read-only memory (ROM), an erasable programmable
read-only memory (EPROM or Flash memory), an optical fiber, and a
portable compact disc read-only memory (CD-ROM). Note that the
computer-usable or computer-readable medium could even be paper or
another suitable medium upon which the program is printed, as the
program can be electronically captured, via, for instance, optical
scanning of the paper or other medium, then compiled, interpreted,
or otherwise processed in a suitable manner, if necessary, and then
stored in a computer memory.
[0040] Embodiments of the present invention, for example, are
described above with reference to block diagrams and/or operational
illustrations of methods, systems, and computer program products
according to embodiments of the invention. The functions/acts noted
in the blocks may occur out of the order as shown in any flowchart.
For example, two blocks shown in succession may in fact be executed
substantially concurrently or the blocks may sometimes be executed
in the reverse order, depending upon the functionality/acts
involved.
[0041] While certain embodiments of the invention have been
described, other embodiments may exist. Furthermore, although
embodiments of the present invention have been described as being
associated with data stored in memory and other storage mediums,
data can also be stored on or read from other types of
computer-readable media, such as secondary storage devices, like
hard disks, floppy disks, or a CD-ROM, a carrier wave from the
Internet, or other forms of RAM or ROM. Further, the disclosed
methods' stages may be modified in any manner, including by
reordering stages and/or inserting or deleting stages, without
departing from the invention.
[0042] All rights including copyrights in the code included herein
are vested in and the property of the Applicant. The Applicant
retains and reserves all rights in the code included herein, and
grants permission to reproduce the material only in connection with
reproduction of the granted patent and for no other purpose.
[0043] While the specification includes examples, the invention's
scope is indicated by the following claims. Furthermore, while the
specification has been described in language specific to structural
features and/or methodological acts, the claims are not limited to
the features or acts described above. Rather, the specific features
and acts described above are disclosed as example for embodiments
of the invention.
* * * * *